Bertolt Brecht’s Mother Courage doesn’t fit the mold of a conventional heroine, or even the mold of a conventional antiheroine. But Kecia Lewis, who plays the role in the Classic Stage Company’s terrific production of “Mother Courage and Her Children,” certainly deserves some sort of badge of honor. Ms. Lewis’s commanding performance would be impressive under any circumstances, but the drama surrounding her undertaking the part makes the achievement all the more remarkable.

As theater watchers are likely to know, Ms. Lewis stepped into the production at the last minute when the star who was first cast, Tonya Pinkins, departed just two days before the originally scheduled opening, eventually citing the traditional artistic differences with her director, Brian Kulick, albeit with nontraditional rancor. When I saw the show on Saturday, Ms. Lewis had given just four performances.

Technically, it showed. She called for assistance a couple of times in the first act — barking the word “Line!” fully in character — and carried and consulted a script not infrequently during the second.

But these necessary aids were surprisingly easy to ignore, because Ms. Lewis’s rendering of her complex character, who doggedly profits from a yearslong war, even as it ravages her family, was so powerful, complex and persuasive. (Brecht might almost approve of Ms. Lewis’s reliance on her script, because it kept us aware of the artifice of the drama even as we were drawn into it — in keeping with his theories of the necessary “alienation” from simplistic emotional involvement in the mechanics of the story.)

Mr. Kulick’s searing production — the last and by any measure the finest of the company’s Brecht cycle, which included productions of “Galileo,”“The Caucasian Chalk Circle” and “A Man’s a Man” — sets the play in the 1990s in both the Democratic Republic of Congo and the Republic of Congo. It is an inspired idea: Though the original is set in 17th-century Europe during the Thirty Years’ War, little alteration of John Willett’s translation proves necessary. Brutal civil wars have been tearing apart African countries for years on end, and the characters and their circumstances feel entirely, grimly, relevant.

The cart that Mother Courage and her three children pull in the original is now a battered truck, from which she sells pretty much anything soldiers and desperate civilians will buy. Ms. Lewis, a chilly look of suspicion forever in her eye, cuts a formidable figure, and is as ferocious in her bargaining as she is protective of her children. When a sergeant and a recruiter try to conscript her older son, Eilif (Curtiss Cook Jr.), into the ranks, she pulls out a long machete, and Ms. Lewis’s hard stare suggests that she would not shy from using it.

Image

Kecia Lewis, center, plays the lead role in the Classic Stage Company’s production of Bertolt Brecht’s “Mother Courage and Her Children.”CreditRichard Termine for The New York Times

But while Mother Courage is haggling with the sergeant over the price of a belt buckle, the recruiter, playing on Eilif’s naïveté and ego, draws him away before she can intervene. “Like the war to nourish you? Have to feed it something, too,” the sergeant mockingly calls, as Mother Courage and the remains of her family depart.

Brecht’s savage, sardonic view of war as a man-made machine that produces as much profit as blood glimmers darkly throughout the show. During the scene in which Mother Courage cannot resist haggling over the price she will pay to ransom her son Swiss Cheese (Deandre Sevon), who has fallen into the hands of the enemy, her hard carapace of ruthlessness melts away, and we see the shellshocked mother, aghast that she has just allowed her son to die to save a few pennies. Fenced in by barbed wire, she grabs at the wire in an instinctive act of self-punishment, a look of dazed contrition on her cold mask of a face.

Several of Classic Stage’s Brecht productions have included new music by Duncan Sheik (“Spring Awakening”), and Ms. Lewis performs his seductive, African-inspired songs in a powerful voice, by turns scathing, lyrical and mournful. (She has a long background in musical theater.)

But her fine performance is just one among many. Mother Courage joins forces at various times with a chaplain whom she orders around blithely. Michael Potts imbues that character with a smiling worldliness just bordering on cynicism. Also seeking Mother Courage’s affections is an army cook (a strong Kevin Mambo), who tries to entice her to join him when he inherits a small inn; she refuses when he tells her that her beloved daughter, the mute Kattrin (Mirirai Sithole), cannot join them. Zenzi Williams brings a tart, embittered edge to the opportunistic Yvette, whose song of sexual exploitation by soldiers is among the musical highlights.

As Eilif, Mr. Cook evolves from a cocky, naïve young man to a cockier, ruthless soldier (he brags about cleverly tricking, then killing, civilians); we also see that when peace briefly breaks out, he’s been turned into a cold killing machine that cannot be stopped. Mr. Sevon is equally good as his boyish younger brother, whom Mother Courage wrongly considers too honest (and too dumb) to get himself into trouble.

And as Kattrin, the young Ms. Sithole is simply extraordinary. Small and rail-thin, suggesting that even Mother Courage’s hard bargain-driving cannot keep her family from edging toward starvation, Ms. Sithole provides the production with a moving emotional center, communicating through gestures, wordless yelps and wounded feeling in her eyes Kattrin’s sensitivity, terror and, ultimately, nobility.

The moment when Kattrin defies her mother and begins beating a drum to warn a nearby town of an imminent attack brings this entirely engrossing production to a hair-raising, then heartbreaking climax. Her eyes now shine with an icy determination, an inheritance from Mother Courage that at the same time proves that she alone has been uncorrupted by the war and her mother’s calculating ways.